Take a snapshot of Bryony Lavery’s play, and it would likely be of the meeting between Ralph, a serial abuser and murderer of pre-teen girls, and Nancy, the mother of one of his victims, who visits him in prison. In fact, although this is the fulcrum on which the play turns, it occupies a single scene out of more than two hours of playing time. Ralph spends much longer under examination by neuro-psychologist Agnetha, whose thesis is that such killers’ behaviour is usually attributable to physically grounded brain malfunctions. Moreover, the majority of the play overall consists of alternating monologues rather than exchanges: for each individual character, the crucial matter is confrontation not with another, but with part of themselves which they have been avoiding.

In one or two respects, Lavery’s drama has dated since its 1998 première: Ralph’s treasured collection of kiddie-porn VHS cassettes now seems quaint, although it may be more unsettling to consider how unquestioned today are laws requiring community disclosure of sex offenders’ details. However, both the narrative superstructure and the underlying preoccupations are as urgent and affecting now as ever. All three characters are facing issues of recognition and coping: Nancy is still imprisoned by her daughter’s murder 20 years on, Ralph is in primitive denial in almost every respect and shows no understanding of remorse, and Agnetha is haunted by her own relationship with a recently deceased colleague.

Lavery may overdo the glacial metaphors (Agnetha is even an Icelandic-American, and shares a patronymic with Björk), but she examines matters with candour and sympathy from a range of angles in what is surely her masterpiece as a playwright. Jonathan Munby’s cast act with skill and sensitivity in front of Luke Halls’ video projections which suggest at once ice and networks of synapses. Neither Suranne Jones as Nancy nor Nina Sosanya as Agnetha overplay, but the sinister focus is Jason Watkins’ Ralph, who commands our attention even as we want to take a shower simply from being in proximity to him. Easy assumptions, sentimentality and mythologizing are rigorously avoided, and one leaves the theatre both emotionally affected and wrapped in thought.

Written for the Financial Times.